kuldeepjambhulkar/Nothing-Glyph ? reverse-engineered prompt

Build me a small web page that recreates a minimalist animated pixel glyph inspired by the Nothing Phone Glyph look.

It should feel clean, dark, and futuristic, with a centered pixel style glyph that changes animation when I use the arrow keys. I want to be able to cycle through a few different modes with the keyboard, and each mode should look clearly different, like subtle light patterns, pulses, or movement. Keep it lightweight and smooth, and make the whole thing work nicely in the browser without extra fuss.

Please make it responsive, simple to use, and visually polished, with the main focus on the animation itself. If you need to check current browser friendly approaches or effects, look them up online first.